In this communication we present a method using Focused Ion Beam (FIB), Energy Filtered TEM (EFTEM) and STEM for semiconductor defects interception and high resolution observation. This method takes benefit of the specific imaging properties of respectively EFTEM and STEM techniques. A demonstration is presented for the observation of dislocations in a silicon integrated circuit.

Silicon defects such as dislocations are one of the major issues in Integrated Circuit fabrication. Due to their low distribution density these silicon defects are not easily observed using TEM cross section. in this paper we present a more appropriate technique using: FIB, EFTEM and STEM for such defects observation. First, in order to improve the probability of defects being present in the specimen, a very thick lamella is prepared using FIB. Then, using an energy filter for eliminating the inelastic electrons needed to allow thick specimen TEM imaging, direct defect localization and observation at medium resolution is carried out. After that, taking advantage of the beam broadening in the STEM, the defect position inside the specimen is more accurately evaluated. For that purpose two STEM observations are carried out from the two opposite specimen surfaces. The comparison of image contrast is used for further FIB specimen thinning. The process can be continued down to a thickness compatible with an acceptable spatial resolution TEM imaging.